Setting the environment Overview of PHP Constants and Variables in PHP

Basharat Mahmood, Department of Computer Science,CIIT,Islamabad,Pakistan.

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Introduction to PHP (Part-2)


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Summary of the previous lecture

• Setting the environment• Overview of PHP• Constants and Variables in PHP


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Outline

• Operators in PHP• Conditional Statements in PHP• Looping Statements• Arrays in PHP


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1. Operators in PHP

• Arithmetic Operators:– +, - ,*, /, %

• Assignment Operators:– =–+= ($a +=$b ), *= , /=– .= ($a .= $b)


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1. Operators in PHP…

Adds $b in $a

Concatenates $b with $a


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• String Operators:– . , .=– $a=“abcd”.”efgh”; $a=abcdefgh– $a.=“ijk”; $a=abcdefghijk

• Increment/decrement Operators:– ++,--–$b=$a++–$b=++$a


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First variable

Second variable

Concatenation

Using .=


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Variable declared

Incremented before display

Incremented after display

Displaying incremented value


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• Logical Operators:– AND, OR, NOT, XOR– &&, ||, !

• Equality Operators:– ==, !=, ===

• Comparison Operators:– >, <, <=, >=


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Integer valueString value

Compares only values

Strict comparison


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2. Conditional Statements

• if statement:if(condition) { }

• if-else statement:if(condition)

{ } else

{ }


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2. Conditional Statements…

• switch statement:switch(variable){case option: actionbreak;..}


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Switch starts

case 0

Case 1


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3. Looping Statements

• for loop• while loop• do-while loop• foreach loop


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3. Looping Statements

• for loopfor($a=0; $a<10; $a++){statements}

• while loopwhile(condition){StatementsIncrement/decrement}


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3. Looping Statements…

• do-while loopdo{StatementsIncrement/decrement}While(condition)

• foreach loop– is used to read an entire array


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For loop

While loop


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Output from for loop

Output from while loop


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Array is declared

Foreach loop starts

Using obtained value


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4. Arrays in PHP

• An array is traditionally defined as a group of items that share certain characteristics

• Each item consists of two components:– the key and a value

• PHP doesn’t require that you assign a size to an array at creation time

• Declaring an array:– $array-name[key]=value


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4. Arrays in PHP…

• Declaring an array:– $array-name[key]=value– $players[0]=“Muhammad Yousuf”;

• Adding element in an array:– $players[1]=“Younus Khan”;

• Accessing element in an array– echo $players[0];


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4. Arrays in PHP…

Declaring array

Adding elements

Foreach loop


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4. Arrays in PHP…


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4. Arrays in PHP…

• Associative arrays:– $array-name[‘element-name’]=value– $players[‘yousuf’]=“Muhammad Yousuf”;

• Adding element in an array:– $players[‘younus’]=“Younus Khan”;

• Accessing element in an array:– echo $players[‘yousuf’];


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4. Arrays in PHP…

• The array(); can also be used to create an array – $array_name=array(item_1,item_2,…item_n);

– $players=array(“M.Yoursuf”,”Imran Khan”);

– $players=array(“Yousuf”=>“M.Yoursuf”,”imran”=>”Imran Khan”);


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4. Arrays in PHP…

Associative array is created using array()

Accessing elements by name


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4. Arrays in PHP…


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4. Arrays in PHP…

• Sorting arrays:– sort()– rsort()


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4. Arrays in PHP…

Array is created

Array is sorted

Array is displayed


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4. Arrays in PHP…


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4. Arrays in PHP…

rsort() is used


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4. Arrays in PHP…


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Summary

• Operators in PHP• Conditional statements• Looping statements• Arrays in PHP


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References

• Chapter 2, “Beginning PHP6,Apache,Mysql web development” by Matt Doyle, Wrox publishers, 2009, ISBN: 0470413964

• Chapter 5, “Beginning PHP and MySQL” by W. Jason Gilmore, Apress publisher, 4th edition; 2010, ISBN-13 (electronic): 978-1-4302-3115-8.

Setting the environment Overview of PHP Constants and Variables in PHP

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